INCOME TAXES - Schedule of the Provision for /(Recovery of) income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Current income taxes (recoveries)
Domestic (Canada)	$ 1.5	$ 1.4	$ 1.0
Foreign	134.6	63.8	85.9
Total current income taxes	136.1	65.2	86.9
Deferred income taxes (recoveries)
Domestic (Canada)	0.0	0.0	0.0
Foreign	(31.9)	(3.6)	(27.9)
Total deferred income taxes (recoveries)	(31.9)	(3.6)	(27.9)
Income tax expense	$ 104.2	$ 61.6	$ 59.0